Taking clonazepam 0.5mg for approx 3 weeks, and now also on Lexapro (escitalopram) in evening. How to wean off clonazepam to avoid insomnia and anxiety symptoms?

Have PCP help. The dose is not high and it is a long acting minor tranquilizer and you haven't taken it for too long so you can cut the dose by half for a week and stop. Have pcp supervise.
Rule of halves. If you are only taking the Clonazepam at bedtime, cut it in half for a week. Then stop. The first night after cutting back will be a little tough, but will improve.